I lived in NJ for 5 years and it doesn't get much more armpit than that
Wait till you move to make that assumption. Gun laws are more lax, but that doesn't mean the police know what the law is. And won't harass you even when you are in the right.
IMHO Cobb and Cherokee are the more desirable counties on the North side of town
More desirable, yes. But I consider Cobb nothing more than DeKalb on the west side of town. It's not as (widespead) bad, but in places it's just as bad. Cherokee is one of the better counties. I'm more familiar with the east side of town. Gwinnet and Rockdale are not bad, very similar to Cobb. Cobb and Gwinnett have premier school systems. IIRC, Gwinnett graduated something like 10,000 last year. There is a reason why so many people are (last 20 years) moving there. (That's why I had to get out of there. Too crowded.) For a higher quality of life, look at Walton and Newton counties on the east side. Walton is the better of the two, but Newton is cheaper (home prices and property taxes). The east side typically has the lightest traffic on average days. But when it's bad, it's real bad. Last week it took me close to 3 hours to get home from work. ~75 miles and typically 1 hr 15 min ride.
Almost anywhere outside of the 30 mile radius is very nice, N,S,E,W.
Make it 45-50 and I'd agree with that statement. I live 30 miles outside of the perimeter, and 15 miles off the interstate. Never had a problem with anybody around here, true Southern Hospitality is still alive in the country. And I have a 50 yard range set up off my back porch. Also have a chicken pen with fresh eggs daily.
If traffic is a large concern to you, stay away from I75, I85 and GA 400 all north of Atlanta. Typically the worst traffic in Atlanta. I20 west of Atlanta gets bad on clear days in the late spring- early fall months (known as the "Sunshine Slowdown"). I20 and US 78 east of Atlanta are typically some of the better commutes. (My biggest problem is going thru DeKalb, the locals can't figure out how to merge onto and off of the highway.) I85, I75, and I675 south of Atlanta I'm not as familiar with. That's because you don't always hear traffic reports from down there. (May be because it's lighter than elsewhere, IDK.)
There are nice areas in the city, but space is extremely tight (you may not mind that, I got to have my room) and prices are substantial. And you still have to deal with the local government, and the liberals run rampant (again that may not bother you).
Wyman